High-speed InGaP/GaAs heterojunction bipolar transistors with buried SiO2 using WSi as the base electrode

High-speed InGaP/GaAs heterojunction bipolar transistors (HBT's) with a small emitter area are described, WSI is used as the base electrode to fabricate HBT's with a narrow base contact width and a buried SiO2 structure, An HBT with an emitter area of 0.8x5 mu m exhibited an f(T) of 105 GHz and an f(max) of 120 GHz. These high values are obtained due to the reduction of C-BC by using buried SiO2 with a narrow base contact width, indicating the great potential of GaAs HBT's for high-speed and low-power circuit applications.